MODULAR PLATING LINE

FIELD OF INVENTION

This invention relates in general to electrolytic and electroless plating lines and more particularly to the design and materials of construction thereof.

BACKGROUND

Vertical plating systems are generally used for electrolytic and electroless plating processes in the field of electronics and general metal finishing. Traditionally, these systems feature a single welded metal tank filled with the chemical solution, or fluid, to be used in the plating process. The substrate to be plated is dipped into a process fluid in the tank and removed when the plating is finished.

The design of these tanks is subject to a number of inefficiencies, especially with regard to maintenance of the system. First, the tank containing the chemical solution must be emptied before maintenance can occur. The emptied chemical solution is often unable to be reused and must be disposed of and replaced when maintenance occurs. Further, the welded design of the tanks is susceptible to failure or can stimulate plate out due to the corrosive nature of the solutions. Plate out occurs when the metal in the solution begins to plate an object or location in the tank that is not the desired substrate to be plated. Poor weld quality and impurities can form a location for plate out in these instances. When a leak or plate out occurs, the entire tank must be drained and replaced leading to significant downtime of the unit. This downtime may be further extended if a replacement tank is not immediately available due to the lead time required for a new welded tank.

Current systems employing single welded tanks often house auxiliary equipment such as heating, cooling, agitation, and dosing equipment within the same housing as the tank. This increases the size and footprint of individual vertical plating systems due to the proximity of the equipment to the welded metal tank. Additionally, this can cause further maintenance issues as the auxiliary equipment may be inaccessible depending on the arrangement of the auxiliary equipment and surrounding vertical plating systems. This can lead to additional downtime and loss of chemical solutions when auxiliary equipment maintenance needs to be performed.

The use of welded tanks can also result in large lead times for new system orders. Current delivery times can be in excess of a year for new vertical plating systems due, in part, to the tank design and construction. From this, there is a need in the industry for alternative designs for vertical plating systems with reduced lead times and better maintainability.

SUMMARY OF THE INVENTION

The present invention is directed to plating processes systems, and methods. The plating system can be used for electrolytic and electroless plating of various substrates. Electrolytic plating can be performed by running an electrical current through a modular plating line filled with a fluid and a substrate that is to be plated. Electroless plating can be performed by a chemical reaction within a fluid. In both electrolytic and electroless plating, a metal can be plated onto a substrate. In the present invention, a constantly recirculating process fluid containing the metal to be plated onto the substrate can undergo electrolytic or electroless plating in a system with reduced maintenance and downtime.

The plating system can be made with rotor molding. To rotor mold the parts for the plating system, an initial mold can be created for each of the parts in the plating system. Plastic is added to the mold which is rotated at high speed to evenly distribute the plastic throughout the mold. The process can result in seamless and weldless molded parts for the plating system. The parts can be molded with plastics included polyvinylidene fluoride (“PVDF”), polypropylene, or polyethylene.

The system and method may include a modular plating line comprising an inner tank, a fluid delivery system positioned inside the inner tank, and a collection sump positioned beneath the inner tank. The fluid delivery system may deliver a process fluid to the inner tank for electroplating a substrate. The substrate can be positioned between two fluid delivery systems and in contact with the process fluid. The inner tank may have an aperture at the bottom thereof to allow fluid to drain from the tank. The system can allow for a constant flow of the process fluid into the inner tank through the fluid delivery system and out of the inner tank through the aperture.

The inner tank can drain through the aperture and into an outer tank. This outer tank can further drain to the collection sump. In this system, the flow into the inner tank through the fluid delivery system can be greater than the flow through the aperture. This can result such that the inner tank can overflow into the outer tank during electrolytic and electroless plating operations.

Alternatively, the system may include a level line which can overflow into an overflow line that can drain to the collection sump. The level line can be positioned adjacent to the inner tank such that the level line is filled to a level equivalent to the inner tank. The overflow line can be positioned such that a high level in the inner tank and level line overflows from the level line into the overflow line prior to overflowing the inner tank. The sump can include a heating unit, a cooling unit, at least one dousing unit, or an agitation unit.

The fluid delivery system used in the modular plating line can include a plurality of nozzles. These nozzles may be offset from one another in both the horizontal and vertical directions. This may provide an even distribution of fluid through the fluid delivery system to the substrate positioned within the inner tank. The system may also include a pump to pump fluid from the collection sump to the fluid delivery system, such that the fluid may be reused. The tanks and fluid delivery system can be formed from molded plastic.

The method may also include operating a modular plating line comprising pumping fluid from a process sump to an inner tank, draining the inner tank through an aperture, and recirculating the fluid back to the process sump. The fluid can be pumped through a fluid delivery system located inside the inner tank. The fluid delivery system can have a plurality of nozzles, which distribute fluid evenly through the inner tank. The nozzles can be offset vertically and horizontally across the face of the fluid delivery system to achieve even fluid delivery. The fluid delivery system can receive fluid pumped from process sump, such that there is a continuous recirculation of fluid from the process sump to the fluid delivery system, to the inner tank, and back to the process sump.

In order to not waste fluid, during a plating process, the fluid can continuously overflow the inner tank into the outer tank and can drain from the outer tank back to the process sump. Alternatively, there can be a level line with a constant level with the inner tank. The level line can overflow into an overflow line which can drain to the process sump.

The plating process system and method can also include methods of maintaining a modular plating line including draining the inner tank to the process sump, removing a supporting frame from around the inner tank, replacing the inner tank, and securing the supporting frame around the inner tank. The supporting frame may secure both the inner and outer tank, or it may secure one of the inner tank or outer tank. There may also be separate supporting frames, with one frame supporting the inner tank and a separate frame supporting the outer tank. The supporting frame can be secured with a quick release mechanism allowing for replacement of the inner tank with minimal maintenance intervention.

As noted, the fluid drained from the tanks can be reused after maintenance is complete as the fluid can be stored in the process sump during maintenance. Moreover, the system may include auxiliary equipment outside of the tanks, and maintenance can be performed on this auxiliary equipment. The auxiliary equipment can be a heating unit, cooling unit, at least one dosing unit, or agitation unit in some embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be better understood on reading the following detailed description of non-limiting embodiments thereof, and on examining the accompanying drawings, in which:

FIG. 1A is a schematic diagram of a modular plating line for the plating process system and method having an inner and outer tank.

FIG. 1B is a schematic diagram of a modular plating line for the plating process system and method having an inner tank, level line, and overflow line.

FIG. 2 is a schematic diagram of a process sump.

FIG. 3 is a three-dimensional drawing of the inner and outer tanks of the modular plating system in a secured position.

FIG. 4 is a three-dimensional drawing of a fluid delivery system.

FIG. 5 is a three-dimensional drawing of an inner tank cutaway along the width of the tank.

FIG. 6 is a three-dimensional drawing of a fluid delivery system positioned inside an inner tank from an overhead view.

DETAILED DESCRIPTION OF THE INVENTION

The foregoing aspects, features and advantages of the present invention will be further appreciated when considered with reference to the following description of preferred embodiments and accompanying drawings, wherein like reference numerals represent like elements. In describing the preferred embodiments illustrated in the appended drawings, specific terminology will be used for the sake of clarity. The invention, however, is not intended to be limited to the specific terms used, and it is to be understood that each specific term includes equivalents that operate in a similar manner to accomplish a similar purpose.

When introducing elements of various embodiments of the present invention, the articles “a,” “an,” “the,” and “said” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. Any examples of operating parameters and/or environmental conditions are not exclusive of other parameters/conditions of the disclosed embodiments. Additionally, it should be understood that references to “one embodiment,” “an embodiment,” “certain embodiments,” or “other embodiments” of the present invention are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. Furthermore, reference to terms such as “above,” “below,” “upper”, “lower”, “side”, “front,” “back,” or other terms regarding orientation are made with reference to the illustrated embodiments and are not intended to be limiting or exclude other orientations.

The present invention provides for a modular plating system with replaceable components. Major components, such as the tanks and fluid delivery system, can be made with molded plastic. This can be done through the use of a rotor molding system. To rotor mold the parts for the plating system, an initial mold can be created for each of the parts in the plating system. Plastic is added to the mold which is rotated at high speed to evenly distribute the plastic throughout the mold. The process can result in seamless and weldless parts for the plating system. The parts can be molded with plastics included polyvinylidene fluoride (“PVDF”), polypropylene, or polyethylene.

FIG. 1A illustrates a modular plating line 100 that can be used in the plating process system and method. Electrolytic and electroless plating is a method by which metal is deposited onto a substrate through various methods. A fluid containing a metal to be plated onto a substrate can be brought into contact with the substrate. In electrolytic plating, an electrical current can be run through the fluid to catalyze the plating onto the substrate. In electroless plating, a chemical reaction can be used to catalyze the plating onto the substrate. The modular plating line 100 can perform electrolytic and electroless plating by a constant circulation of process fluid through the system.

The modular plating line 100 can have an inner tank 102 and an outer tank 104. The inner tank 102 can be positioned substantially within the outer tank 104. The inner tank 102 and outer tank 104 can be made with molded plastic forming methods. The use of molded plastic allows for greater production speeds of these tanks than is possible using traditional welded methods. Additionally, welds used in traditional tanks are often weak points in the construction of the tank and can be prone to failure due to chemical attack.

The system can be designed such that a process fluid can initially flow into the inner tank 102. The process fluid can be any fluid containing a material to be plated onto the substrate 103 located within the inner tank 102 through either electrolytic or electroless plating methods. The process fluid contained within inner tank 102 can drain to the outer tank 104 through an aperture 106 in the bottom of the inner tank 102. This can result such that the process fluid within the inner tank 102 can fully drain to the outer tank 104 through the aperture 106 when the process fluid stops flowing to the inner tank 102. This can be the case during maintenance of the modular plating line 100 so that the process fluid is not present in the inner tank 102 during the maintenance.

The aperture 106 can be sized such that the flow through the aperture 106 is less than the normal flow of the process fluid into the inner tank 102 during the electrolytic or electroless plating process. In normal operating conditions, this can result such that the inner tank 102 remains full of process fluid even while draining to the outer tank 104 through the aperture 106. This can keep the substrate 103 fully submerged within the process fluid during the plating process. As a result of this flow imbalance, the fluid in the inner tank 102 can overflow the inner tank 102 and flow into the outer tank 104 in addition to flowing through the aperture 106. During the electrolytic or electroless plating process, process fluid can flow from the inner tank 102 to the outer tank 104 both through the aperture 106 and by overflowing the inner tank 102. The outer tank 104 can therefore have a higher elevation than the inner tank 102 such that process fluid overflowing the inner tank 102 is contained within the outer tank 104 and does not exit the modular plating line 100.

Fluid in the outer tank 104 drains by gravity to a sump 108. The drain from the outer tank 104 to the sump 108 can be sized for flows larger than the maximum flow of process fluid into the inner tank 102. This can prevent process fluid from overflowing the outer tank 104. The sump 108 can be connected to multiple modular plating lines 100 such that multiple outer tanks 104 can drain to the sump. The sump 108 can be sized to contain the process fluid of the modular plating lines 100 when they are down for maintenance. The sump 108 can also be used to adjust the properties of the process fluid during the electrolytic or electroless plating process. Unlike traditional systems which require that the process fluids are dumped to waste when undergoing maintenance, the sump 108 can allow the same process fluid to be used both before and after maintenance.

Fluid from the sump 108 can be pumped to the inner tank 102 through pumps 110. The fluid can pass through a fluid delivery system 112 before entering the inner tank 102. The fluid delivery systems 112 can be substantially inside the inner tank 102. There can be a fluid delivery system 112 associated with each pump 110 pumping fluid from the sump 108. The fluid delivery system 112 is described in greater detail with respect to FIG. 4.

The fluid delivery system 112 can also be made with a molded plastic similar to the inner and outer tanks 102 & 104. This can result in similar advantages where replacement parts can be easily manufactured, for example through the use of rotor molding. Additionally, molded fluid delivery systems 112 reduce the requirement of welding within the system which can be prone to leaks or plate out locations.

FIG. 1B illustrates a modular plating line 100 with only an inner tank 102. In this configuration there can be a level line 114 and an overflow line 116. Both the level line 114 and the overflow line 116 can be connected to the aperture 106 and drain to the sump 108. The level line 114 can be connected upstream of the aperture 106 and the overflow line 116 can be connected downstream of the aperture 106. In this configuration, when the process fluid is no longer pumped into the inner tank 102, the inner tank 102, level line 114, and overflow line 116 can all drain to the sump 108 such that there may not be process fluid within the modular plating line 100. This can allow for maintenance of the modular plating line 100 without the presence of process fluid.

In this configuration, the flow rate into the inner tank 102 through the fluid delivery systems 112 can be higher than the amount of flow that can pass through the aperture 106. This can result in process fluid backing up into the level line 114 such that there is an equivalent fluid level in the inner tank 102 and level line 114. The level can continue to increase in the level line 114 and inner tank 102 until the level of the overflow line 116 is reached. Upon reaching this level, the process fluid can overflow from the level line 114 and into the overflow line 116 where it can be carried to the sump 108. The level line 114 can further have a level sensor 118 to confirm proper level in both the level line 114 and inner tank 102.

FIG. 2 illustrates a sump 108 that can be used in the plating process system and method. The sump 108 can have at least one line running to pumps 110. There can also be at least one line coming from the apertures 106. These lines can make up the flow circuit for the modular plating line 100 in and out of the sump 108.

The sump 108 can include a number of ways to modify the process fluid. The sump 108 can include a heater 202 for increasing the temperature of the fluid within the sump 108. The sump 108 can also include a heat exchanger 204. The heat exchanger 204 can be used to heat the fluid if there is not a separate heater 202. The heat exchanger 204 can also be used to cool the fluid by running chilled water or any other appropriate fluid through the heat exchanger 204. The heat exchanger 204 can be used to heat the process fluid within the sump when coming back online from maintenance when the fluid has been sitting for an extended period of time or when higher temperature operations are required for the system. During operation, the heat exchanger 204 can be used to cool the process fluid due to excess heat generated by the electrolytic or electroless plating reactions and for use in lower temperature operations of the system.

The sump 108 can also have at least one dosing system for modifying the fluid within the sump 108. The at least one dosing system can include a sulfuric acid dosing system 206, a carrier dosing system 208, a leveler dosing system 210, a brightener dosing system 212, a deionized water (“DI water”) dosing system 214, and any other appropriate dosing system. The dosing systems can be operated with valves to control the flow of each component into the sump 108. The sump 108 can also include a mixer 216 with mixer motor 218 to ensure even distribution of the dosed chemicals throughout the fluid. The mixer 216 can also be an air agitation unit instead of a physical mixer. The mixer 216 can prevent localized high and low concentration regions within the sump 108 resulting in a consistent process fluid that is delivered to the modular plating line 100. The mixer 216 can also be used in combination with the heat exchanger 204 or heater 202 to ensure proper temperature distribution within the fluid.

The sulfuric acid dosing system 206 can be used to lower the pH or increase the ions of the solution resulting in improved conductivity of the process fluid within the sump 108. The carrier dosing system 208 can be used to increase the concentration of a carrier with the type of metal to be plated onto the substrate in the sump 108. The leveler dosing system 210 can be used to increase the level within the sump 108. The brightener dosing system 212 can be used to add a brightening agent which can result in a visually brighter plating onto the substrate. The DI water dosing system 214 can be used to add water to the sump 108 to correct for evaporation of material during operation of the modular plating line 100.

The sump 108 can also include a transfer line 220. The transfer line 220 can connect to other sumps 108 in a series of modular plating lines 100. This can be used to transfer fluid to and from different sumps 108. The sump can also include a waste line 222 which can be used to dispose of the fluid for any appropriate reason.

FIG. 3 is an embodiment of a tank setup 300 with associated support structure 302. The tank system can be held in place by a supporting structure 302. The supporting structure can be secured by a quick release mechanism such that the tank system is secure during normal operation of the unit. As shown in FIG. 3, the support structure may comprise a plurality of horizontal and vertical support bars to hold the tank in place.

The supporting structure 302 can be split into a first half of the supporting structure 304 and a second half of the supporting structure 306. Here the quick release mechanism can be released such that the two supporting structure halves 304 and 306 can be separated. This can allow access to remove and replace the tank or fluid delivery system depending on the maintenance requirements. The molded plastic design of the tank system can be used such that the tank and fluid delivery systems can be readily replaced with similarly sized tanks or fluid delivery systems.

FIG. 4 illustrates a fluid delivery system 112 for the plating process system and method. The fluid delivery system 112 can have inlet lines 402 to the fluid delivery system 112. The inlet lines 402 can deliver fluid pumped from the sump 108 to the fluid delivery system 112. The fluid delivery system 112 can have a plurality of nozzles 404. Fluid entering the fluid delivery system 112 through the inlet line 402 can exit the fluid delivery system 112 through the plurality of nozzles 404 and into the inner tank 102. The plurality of nozzles 404 can be sealed to prevent oxygen from entering the fluid delivery system 112 through counterflow.

The fluid delivery system 112 can include a mixed metal oxide (“MMO”) anode mesh on the surface of the fluid delivery system 112. A plating diaphragm can further cover the MMO anode mesh. The MMO anode mesh can provide the anode for electrolytic plating while having high corrosion resistance during electroless plating. A separate cathode can also be provided to complete the electrical circuit during electrolytic plating.

The fluid delivery system 112 can also be made through a rotor molding process. This can result in a fluid delivery system 112 that may not include any seam or weld from production of the fluid delivery system.

FIG. 5 illustrates a cut-away view of the internals of an outer tank 104 along the width of the outer tank 104. The aperture 106 is shown which can be used to drain the inner tank as provided above. The floor 502 of the outer tank 104 can be sloped to allow fluids to drain to the aperture 106. Also shown are vertical ridges 504 of the outer tank 104. The vertical ridges 504 can be used to provide additional rigidity for the outer tank 104. Additionally, the vertical ridges 504 can be used to support the inner tank 102 and provide channels for the overflow from the inner tank 102 into the outer tank 104. For example, the vertical ridges 504 provide for a gap in the areas to either side of each ridge between the outer tank and inner tank when the inner tank is positioned within the outer tank. Horizontal ridges 506 can be associated with a support structure for the outer tank 104. For example, the horizontal ridges can be positioned such that they line up with lateral support bars of a support structure, such as the support structure shown in FIG. 3.

FIG. 6 illustrates a fluid delivery system 112 positioned inside an inner tank 102 shown from an overhead perspective. Substrates to be treated by the plating line are positioned between the two vertical fluid delivery systems 112 and fully within the inner tank 102. The substrates can be suspended above the bottom of the inner tank 102 and below the upper level of the process fluid within the inner tank 102. An appropriate process fluid is then pumped through inlet lines 402 and exits through the plurality of nozzles 404 where the fluid can contact the substrate. The electrolytic or electroless plating process can occur within this tank either through providing an electrical current or a chemical reaction resulting in plating the substrate. Fluid can exit the inner tank 102 through the aperture 106 to drain into the sump located below the system. This can result in constant fluid circulation from the fluid delivery systems 112, through the inner tank 102, and out the aperture 106 for plating the substrate. After plating is complete, the substrate can be removed from the inner tank 102 and a new substrate can be inserted.

Although the technology herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present technology. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present technology as defined by the appended claims.

MODULAR PLATING LINE

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